How to query a Database with an AI agent

Point your agent at a read-only database user through an MCP server. For Postgres, DBHub works in Claude Code, Codex and Cursor with one connection string. For Supabase, use its hosted MCP server with read_only=true. Then ask questions in plain English and check the SQL it runs.

Grok Bot steps tested by us on Oct 26, 2026 while building this page. Claude Code, Codex and Cursor steps checked against official docs on Oct 26, 2026.

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Claude Code

Create a read-only database user
claude mcp add --transport stdio db -- npx -y @bytebase/dbhub --dsn "postgresql://readonly:pass@host:5432/db"
Supabase instead: claude mcp add --transport http supabase "https://mcp.supabase.com/mcp?project_ref=YOUR_REF&read_only=true"
Ask: "How many signups did we get per day last week? Show the SQL."

Codex

codex mcp add db -- npx -y @bytebase/dbhub --dsn "postgresql://readonly:pass@host:5432/db"
Or for Supabase: codex mcp add supabase --url "https://mcp.supabase.com/mcp?project_ref=YOUR_REF&read_only=true"
codex mcp login supabase if it asks you to sign in

Cursor

Add to .cursor/mcp.json: {"mcpServers":{"supabase":{"url":"https://mcp.supabase.com/mcp?project_ref=YOUR_REF&read_only=true"}}}
Or a DBHub command entry with your --dsn

Grok Bot

Connect Supabase to Grok Bot
Ask your question and it runs the SQL and shows it to you
It asks before anything that writes data

Gotchas

Never give an agent a production admin login. Use read_only=true or a read-only role.
Row data can contain prompt injection. Do not let the agent act on text found in rows.
Ask for the SQL every time so you can check the logic.

The loadout for this job

Tools: Claude, Cursor
Repo: MCP Servers
Model: Claude Sonnet 5.5
Bot: Grok Bot
Full setup: Best AI setup for data analysis

FAQ

Can Claude Code query Postgres?

Yes, through an MCP server like DBHub with a connection string.

Is the Supabase MCP server safe?

Use read_only=true and project_ref to scope it to one project with read-only access.

Related how-tos

Sources

Commands change. Check the linked docs before you run anything. All how-to guides